Musnad Ahmad 1153:791

Husayn narrated to us, he said: Isra'il narrated to us, from al-Miqdam ibn Shurayh, from his father, from 'Aishah, she said: The Messenger of Allah, peace and blessings of Allah be upon him, went out to the desert to the camels of the charity. He gave his wives a camel each, except for me. I said: "O Messenger of Allah, you gave them a camel each, except for me." So he gave me a dark-colored, difficult camel that had not been ridden. He said: "O 'Aishah, be gentle with it, for gentleness does not enter into anything but it adorns it, and it does not depart from anything but it disgraces it."